Project Summary The long-term goal of this project is to enable the development of more effective treatments for presbyopia, the loss of near vision with age, by providing new insight into the mechanism behind presbyopia. The prevailing theory suggests that presbyopia is due mainly to age-related changes in the stiffness of the lens, but alternative theories have been proposed suggesting that age-related changes in the ciliary muscle may play a significant role. Age-related changes in the function of the ciliary muscle have been difficult to characterize in vivo due to the lack of suitable clinical imaging technology. The project will address two critical barriers in presbyopia research: a) the lack of methods to accurately quantify the response of the ciliary muscle during accommodation and b) the lack of knowledge of age-related changes to the behavior of the ciliary muscle as it accommodates. The project has two specific aims: Aim 1: Develop computational tools to quantify accommodative response from OCT images of the ciliary muscle We will develop computational tools to segment the ciliary muscle boundary from OCT images and to model and quantify the segmented ciliary muscle contour and its changes with accommodation. Aim 2: Characterize age-dependence of the accommodative dynamics of the ciliary muscle We will image the response of the ciliary muscle during accommodation in 40 subjects from ages 20 to 60. The dynamics of the ciliary muscle during accommodation will be measured using the computational tools developed in Aim 1 and compared as a function of age. The project will produce a new method to quantify the response of the ciliary muscle, which will significantly advance our capability to characterize ciliary muscle function. The project will also extend our understanding of age-related changes to the function of the ciliary muscle, which will help clarify the role of the ciliary muscle in presbyopia. The results of this project will be important towards improving treatments for presbyopia that are currently under development, since they will provide new ways to evaluate treatment efficacy and enhance our understanding of how age-related changes in ciliary muscle function impact treatment outcome.